Study On The Process Of Preparation Of Soda Ash With Brine By Double Decomposition

Raw material for the production transform from sea salt to high purity vacuum salt making and bittern in China's Soda Industry,because of the requirement for environmental protection.Our country have abundant underground salt caverns, empoldering local resources advantage,the preparation of Soda Ash with Brine is of great practical value.This paper gives an introduction to a new technology for the preparation of Soda Ash with Brine and Ammonium Bicarbonate by the method of addition salting-out agent.the process of preparation of Soda Ash and ammonium chloride with Brine by double decomposition,the yield of Sodium Bicarbonate is general 70%～78%,In order to improve the conversion rate of reaction process,study on using the method of addition salting-out agent,through the salting-out effect of salting-out agent, making the solubility of salt decrease,more salts will crystal separation,experimental determination choose high boiling point salting-out agent D,the yield of Sodium Bicarbonate could be increased to 90%above.Through Single factor experiment and orthogonal test,it can get the suitable technological conditions of salting out method: salting-out agent:sodium chloride(molar ratio)=1.0:1.0,reaction temperature is 35℃,n(NaCl)/n(NH₄HCO₃)/=1.0,reaction time is 120min. According to discuss influencing factors on reaction rate,determined the first step of reaction is controlled by chemical reaction,a first order kinetics,and infers its dynamics model:-ln(1-x)=0.4981×C_A0⁰.1458exp(-9.046×10³/RT)t+0.76With the second step,we can get the soda ash by calcining Sodium Bicarbonate. experiment research into calcining time and temperature influence on loss on ignition, determined calcining temperature is 200-240℃,calcining time is 30～35min,The product Soda Ash gained in experiment meets the quality requirements of GB210.1-2004â…¡.Sodium chloride crystal separation from filtrate by vacuum and high temperatur evaporating,ammonium chloride crystal separation at low temperature,the experimental results indicate that sodium chloride and ammonium chloride have high purity together when evaporated water quantity reached 42%volume of filtrate.The obtained sodium chloride contain NaCl%=97.1%;the terminal cooling temperature of ammonium chloride filtrate is 20℃,the drying temperature of ammonium chloride is 60～70℃,The product ammonium chloride gained in experiment meets the quality requirements of GB2946-1992,attained to the agricultural request.salting-out agent and residual liquid of separating ammonium chloride can use circularly.This process with brine as raw material instead of sea salt,reducing cost of raw material,improving benefit of economy;addition salting-out agent,improve the productivity;salting-out agent does not need evaporation,low energy consumption; This process has many advantages,such as simpler,short process flow,simple equipment,less investment,high profit and low pollution.